Gas-insulated switchgear, in which components such as a breaker and a disconnector are housed in a grounded airtight container and insulating gas is filled, is widely used as switchgear in power plants and substations because of excellent safety and maintainability, and suitability for downsizing of a system.
Generally, when a power receiving substation and the like are constructed using gas-insulated switchgear, assembly work of each circuit that includes a main bus is performed at a factory. Then, connection of buses between circuits is performed at a site, thereby reducing man-hours required for installation at the site. Because the assembly work of the gas-insulated switchgear is performed separately for each circuit, each circuit includes a part tolerance and a dimensional deviation caused in assembly. Therefore, by arranging a bellows at a joint at which two buses are connected. to absorb the deviation, connection of buses is simplified. In addition, considering disassembling for minimization of power-cut range, which may be required in future at the time of expansion or at the time of accident, and re-assemblability, bellows are arranged at appropriate positions. However, because bellows are expensive, it is desired that the number of bellows be reduced to cut costs.
In the technique disclosed in Patent Document 1, the number of bellows is reduced in double-bus gas-insulated switchgear having a vertical breaker. Bellows are conventionally arranged at both ends of two unit bus pipes to connect respective circuits. In Patent Document 1, bellows are arranged only at one ends of the unit bus pipes. The bellows are arranged between two gas-insulated switch gear that are adjacent such that the bellows are alternately provided on the unit bus pipes.
In the technique disclosed in Patent Document 2, in double-bus gas-insulated switchgear in which a breaker is arranged horizontally and buses are arranged thereabove in a T-shape, a frame is further arranged under a frame that supports the horizontal breaker, thereby achieving a structure that enables easy disassembling of a breaker alone.    Patent Document 1: Unexamined Utility Model Application Publication No. S56-101118    Patent Document 2: International Publication No. 2000/022708 Pamphlet